=== modified file 'account/account.py'
--- account/account.py	2010-03-23 07:24:07 +0000
+++ account/account.py	2010-03-30 13:00:05 +0000

@@ -570,13 +571,29 @@
     _order = "date_start"
 
     def _check_duration(self,cr,uid,ids):
-        obj_fy=self.browse(cr,uid,ids[0])
+        obj_fy = self.browse(cr,uid,ids[0])
         if obj_fy.date_stop < obj_fy.date_start:
             return False
         return True
 
+    def _check_fiscal_year(self, cr, uid, ids, context={}):
+        obj_fiscal_ids = self.search(cr, uid, [], context=context)
+        obj_fiscal_ids.remove(ids[0])
+        data_fiscal_yr = self.browse(cr, uid, obj_fiscal_ids, context=context)
+        current_fiscal_yr = self.browse(cr, uid, ids, context=context)[0]
+        for dates in data_fiscal_yr:
+            # Condition to check if the current fiscal year falls in between any previously defined fiscal year
+            if dates.date_start <= current_fiscal_yr['date_start'] <= dates.date_stop or dates.date_start <= current_fiscal_yr['date_stop'] <= dates.date_stop:
+                return False
+            # Condition to check whether there exist any previously defined fiscal year falling in between the newly created fiscal year
+            elif current_fiscal_yr['date_start'] <= dates.date_start <= current_fiscal_yr['date_stop'] or current_fiscal_yr['date_start']<= dates.date_start <= current_fiscal_yr['date_stop']:
+                return False
+        return True
+
     _constraints = [
-        (_check_duration, 'Error ! The duration of the Fiscal Year is invalid. ', ['date_stop'])
+        (_check_duration, 'Error ! The duration of the Fiscal Year is invalid. ', ['date_stop']),
+        (_check_fiscal_year, 'Error ! This Fiscal Year overlaps an existing Fiscal Year',['date_start','date_stop'])
+
     ]
 
     def create_period3(self,cr, uid, ids, context={}):